Switch mode power supplies which take an AC power supply and convert the AC power supply to a DC voltage and current are well known. Typically, such power supplies include an AC to DC converter at the input which takes the AC power supply, rectifies the AC power and thereby converts the AC power to the DC power which then is applied to the switching regulator. The switching regulator then produces output voltage and current as required by the load. Typically, such a prior art circuit includes a rectifier. The rectifier might very well comprise a rectifying bridge as shown in FIG. 1 consisting of four diodes such as diodes D1, D2, D3 and D4 and storage capacitors such as capacitors C3 and C4 for storing the charge at a selected voltage which is then used to drive the switching regulator 14 of the switch mode power supply. The capacitors C3, C4 store the charge from the rectifier from cycle to cycle of the AC input power supply. When the switch mode power supply is turned on and an AC input voltage is suddenly applied to input terminals 11a and 11b, capacitors C3 and C4 have zero voltage across them and thus act as a short circuit. In response, a large rush of current passes through these capacitors. The full wave rectifier comprising diodes D1, D2, D3 and D4 passes a positive voltage to capacitors C3 and C4 with the result that these capacitors conduct a very large current. Typically, in the prior art a resistor R3 as shown in FIG. 1 is placed in series to input terminal 11a to limit the amount of current which can be drawn by the AC to DC input conversion stage of the switch mode power supply. Resistor R3 is typically placed in parallel with a relay RE1 which during the startup portion of the operation of the switch mode power supply is left open. When the capacitors C3 and C4 have substantially charged, relay RE1 is typically closed. If capacitor C3 and C4 are not fully charged, then a surge of current passes from input lead 11a to the full wave rectifier and the amount of this surge is inversely proportional to the size of resistor R3. Prior to the closing of relay RE1, the current on input lead 11a which passes through resistor R3 is rectified by the full wave rectifier and charges capacitor C3 and C4. Only that portion of the input voltage which is in excess of the voltage across capacitors C3 and C4 causes current to flow through resistor R3. However, capacitors C3 and C4 are continuously discharging through resistors R1 and R2. Consequently, to bring the voltage across capacitors C3 and C4 as close as possible to the intended voltage during normal steady state operation of the switch mode power supply, resistor R3 must be made quite small. At the same time, to effectively limit the input current during the initial start-up of the AC to DC conversion stage, resistor R3 should be quite large. Accordingly, there is a conflict in sizing R3 between the requirement that R3 be large to effectively limit the input current to the switch mode power supply during the initial portion of the start-up phase and be small to allow filter capacitors C3 and C4 (also called storage capacitors) to charge as closely as possible to the peak line voltage applied across input terminals 11a and 11b. In practice, the compromise between these two conflicting requirements on resistor R3 results in resistor R3 being made quite small. Typically, during normal operation the initial current surge across current limiting resistor R3 is for a sufficiently small time that R3 does not significantly heat above its design limits. However, if a load is prematurely connected to the switch mode power supply during the start-up phase or a short occurs in the switch mode power supply during the turning on of the power supply, then the initial current through resistor R3 lasts for a much longer period than originally intended and current limiting resistor R3 burns out.